Exposed Romex on garage ceiling?

I want to add a 110v outlet and a 220v outlet to my workshop at the far side of my garage (approx 25 ft from the breaker panel). The main breaker panel is in the garage - and the garage ceilings are 12ft high. The garage is completely insulated and drywalled and running the wires above the garage ceiling in the attic area would be difficult due to small space and to insulation. Thinking it may not be right to run exposed Romex along the drywalled ceiling and it may not be right to run Romex inside a conduit, would you advise running individual #12 wires inside a conduit to my workshop?